JP3431327B2 - Three-stage extension zoom lens barrel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-stage extension zoom lens barrel used in compact cameras and the like.

[0002]

2. Description of the Related Art Compact cameras equipped with a recent zoom lens are designed to reduce the storage length.
It has a structure in which the lens barrel is extended from the camera body when used, and recently, a compact camera equipped with a three-stage extension zoom lens has been commercialized.

However, in a conventional compact camera equipped with a three-stage extension zoom lens, although the lens barrel has been succeeded in shortening the storage length by virtue of the three-stage extension structure, a mirror provided inside the lens barrel. Since the number of cylindrical members for driving the cylinders and the number of driving members have increased, the size of the lens barrel in the radial direction has increased, and as a result, the compact camera cannot be made compact in height and width.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. The expansion mechanism and the drive mechanism are simple, and the size of the lens barrel in the radial direction is not increased.
The purpose is to obtain a zoom lens barrel with a stepwise extension.

[0005]

SUMMARY OF THE INVENTION A three-stage extension zoom lens barrel according to the present invention includes a fixed tubular member; a first extension barrel which is helicoidally coupled to the fixed tubular member; and a helicoidally coupled to the first extension barrel. A second delivery lens barrel; a third delivery lens barrel helicoidally coupled to the second delivery lens barrel; a front lens group supported in the third delivery lens barrel; and in the second delivery lens barrel. A rear group lens that is supported; a drive unit that rotates the first delivery lens barrel with respect to the fixed tubular member; and a movable unit in the optical axis direction together with the first delivery lens barrel and with respect to the first delivery lens barrel. And a rotatable member that relatively rotates and that rotates the second delivery barrel.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments. FIG. 1 shows a three-stage extension zoom lens barrel 10 to which the present invention is applied, which is integrated with a compact camera. In this zoom lens barrel 10, the front lens group L1
Zooming is performed by changing the distance between the rear lens group L2 and the rear lens group L2, and focusing is performed by moving the front lens group L1 back and forth.

A fixed cylindrical member 13 is fixed to the front part of an aperture plate 12 that forms the aperture 11 and is fixed inside the camera so as to be adjacent to the aperture plate 12. On the inner peripheral surface of the fixed cylindrical member 13, a female helicoid 13a and three lead grooves 13b having the same shape and larger leads than the female helicoid 13a and having equal intervals are formed. As shown in FIG. 4, each of the lead grooves 13b is formed on the inner peripheral surface of the fixed tubular member 13 with a part of the female helicoid 13a being cut away.

Further, the fixed cylindrical member 13 is formed with a notch groove 13c extending parallel to the optical axis O. This notch groove 1
A pinion shaft 15 is rotatably provided in 3c along the cutout groove 13c. The pinion shaft 15 has a hollow shaft portion 15a rotatably fitted on a shaft 14 extending parallel to the optical axis O. On the hollow shaft portion 15a, a plurality of pinion gear portions 15b are integrally formed at intervals from each other. Axis 14
Has one end fixed to a support plate 16 fixed inside the camera and the other end fixed to a fixed tubular member 13. A drive pinion (not shown) of a zoom motor M provided inside the camera is screwed into the pinion gear portion 15b.

A male helicoid 18a formed on the rear portion of the outer peripheral surface of the first feeding lens barrel 18 is screwed into the female helicoid 13a of the fixed tubular member 13. This first delivery barrel 18
On the same circumferential surface where the male helicoid 18a is formed,
A plurality of outer peripheral gear portions 18b parallel to the male helicoid 18a are formed. The pinion gear portion 15b of the pinion shaft 15 is meshed with the outer peripheral gear portion 18b. A male helicoid 18a is provided between the outer peripheral gear portions 18b.
At least one thread is formed. The structure in which the screw thread of the male helicoid 18a is interposed between the outer peripheral gear portions 18b prevents the first delivery barrel 18 from falling with respect to the fixed tubular member 13. Further, the pinion gear portion 15b of the pinion shaft 15 always meshes with any of the plurality of outer peripheral gear portions 18b regardless of the moving position of the first delivery barrel 18 with respect to the fixed tubular member 13, and between the outer peripheral gear portions 18b. The male helicoid 18a is formed as a plurality of pinion gear portions 15b spaced from each other so that the threads of the male helicoid 18a do not interfere with the pinion gear portion 15b. The upper half of FIG. 5 shows the positional relationship between the first delivery barrel 18 and the pinion shaft 15 when the first delivery barrel 18 is most extended from the fixed tubular member 13, and the lower half of FIG. The positional relationship between the first delivery lens barrel 18 and the pinion shaft 15 when the one delivery lens barrel 18 is housed in the fixed tubular member 13 is shown.

On the inner peripheral surface of the first payoff lens barrel 18, the same inclination as that of the female helicoid 13a (for example, the female helicoid 1) is provided.
If 3a has a right-hand thread, the same right-hand thread) female helicoid 1
8d is formed. Further, on the inner peripheral surface of the first payoff lens barrel 18, the inclination is opposite to the inclination of the female helicoid 13a.
Three lead grooves 18e having the same shape and equal intervals are formed. Each lead groove 18e has a female helicoid 18
It is formed on the inner peripheral surface of the first delivery barrel 18 with a part of d cut away.

Inside the first delivery lens barrel 18, there is disposed a rotating member 19 which is movable integrally with the first delivery lens barrel 18 in the optical axis O direction and is rotatable relative to the first delivery lens barrel 18. First delivery lens barrel 18
An annular groove 18c is formed in the rear portion of the inner peripheral surface along the circumferential direction. The rotating member 19 is formed with a flange portion 19a extending outward in the radial direction. Rotating member 19
By rotatably engaging the flange portion 19a with the annular groove 18c, the first feeding lens barrel 18 and the optical axis O
It is movable in one direction and is relatively rotatable.
Further, the rotation member 19 is provided with an engagement protrusion 19 which is located rearward of the flange portion 19b and protrudes outward in the radial direction.
Three b are formed at equal intervals in the circumferential direction. Each of the engagement protrusions 19b corresponds to the corresponding lead groove 13 of the fixed tubular member 13.
respectively engaged with b. Further, the rotating member 19 is formed with three drive arms 19c extending forward in the circumferential direction at equal intervals.

With the above structure, when the pinion shaft 15 is rotated in one direction by the zoom motor M, the first delivery barrel 18 causes the pinion gear portion 15b and the outer peripheral gear portion 1 to move.
It is rotated via 8b, and at the same time as this rotation, it is paid out from the fixed cylindrical member 13 due to the relationship between the female helicoid 13a and the male helicoid 18a. At the same time, the rotating member 19
Lead groove 13 having a larger lead than the female helicoid 13a
b and the engaging projection 19b, the first extension lens barrel 18
On the other hand, it largely rotates in the same direction as the rotation direction of the first delivery barrel 18. At this time, the amount of rotation of the rotating member 19 with respect to the fixed tubular member 13 exceeds the amount of rotation of the first delivery barrel 18 with respect to the fixed tubular member 13.

A male helicoid 20a formed at the rear portion of the outer peripheral surface of the second payoff barrel 20 is screwed into the female helicoid 18d of the first payoff barrel 18. In addition, the second delivery barrel 20
A plurality of elongated holes 20b are formed in the rear portion of the outer peripheral surface of the male helicoid 20a along the circumferential direction so as to be located behind the male helicoid 20a.

Inside the second delivery lens barrel 20, a linear movement member 21 that moves integrally with the second delivery lens barrel 20 in the optical axis O direction.
Is provided. The straight-moving member 21 is formed with three straight-moving keys 21a extending forward at equal intervals in the circumferential direction. A pin 21b protruding outward in the radial direction is formed at the rear portion of each straight key 21a. Each of the pins 21b passes through the elongated hole 20b of the second delivery barrel 20 and is engaged with the corresponding lead groove 18e of the first delivery barrel 18.

A rear lens group frame member 28 for supporting the rear lens group L2 is provided inside the linear movement member 21. The rear lens group frame member 28 is formed with three pins 28a which are projected outward in the radial direction at equal intervals in the circumferential direction. Each pin 28a has an elongated hole 21 formed in each straight-moving key 21a of the straight-moving member 21 and extending in the optical axis O direction.
It passes through e and engages with three cam grooves 20f formed in the inner surface of the second delivery barrel 20 in the same shape and at equal intervals.

An inner flange 20c is integrally formed at the rear end portion of the second payoff lens barrel 20, and extends in parallel with the optical axis O along the circumferential direction of the inner flange 20c.
Three rotation transmission holes 20d are formed. The drive arm portion 19c of the rotating member 19 is inserted through these rotation transmitting holes 20 so as to be slidable in the optical axis O direction without a gap in the circumferential direction. With the above structure, the first delivery lens barrel 18
The rotating member 19 rotates with respect to the first delivering lens barrel 18, and this rotation is transmitted to the second delivering lens barrel 20 via the drive arm portion 19c and the rotation transmitting hole 20d. As a result, the second delivery barrel 20 is extended forward while rotating relative to the first delivery barrel 18 due to the relationship between the male helicoid 20a and the female helicoid 18d. At the same time, the rectilinear movement member 21 rotates in a direction opposite to the rotation direction of the second delivery barrel 20 due to the engagement relationship between the pin 21b and the lead groove 18e, and does not rotate relative to the fixed tubular member 13. It moves forward together with the second delivery lens barrel 20. In other words, the lead of the lead groove 18 e does not rotate relative to the fixed tubular member 13 when the second delivery lens barrel 20 is delivered while the second delivery lens barrel 2 is being rotated.
It is strictly set to a predetermined lead so as to move forward with 0. From the above description, it is understood that the rectilinear movement member 21 is guided rectilinearly by the combined rotational movement of the first delivery barrel 18 and the second delivery barrel 20.

A female helicoid 20e having the same inclination as the inclination of the female helicoid 18d of the first feeding lens barrel 18 is formed on the inner peripheral surface of the second feeding lens barrel 20. This female helicoid 2
A male helicoid 22a formed at the rear portion of the outer peripheral surface of the third payoff lens barrel 22 is screwed into 0e. In addition, the third delivery barrel 2
A shutter block mounting member 23 is fixed to the inner peripheral surface of 2. The shutter block mounting member 23 is provided with three support arms 23a extending forward and equidistantly in the circumferential direction, and a known shutter block 24 is fixed to the support arms 23a. That is, the third delivery barrel 2
A known shutter block 24 is fixed to the inside of 2 via a shutter block mounting member 23. A known barrier mechanism 30 for opening and closing the taking lens opening 30a is provided at the tip of the third delivery barrel 22.

A female helicoid 24a is formed on the inner peripheral surface of the shutter block 24.
a, a front lens group frame member 29 that supports the front lens group L1.
The male helicoid 29a formed in the above is screwed. As is well known, the shutter block 24 is driven by a drive pin 24b based on a subject distance signal from a distance measuring device (not shown).
Also, the front lens group L1 is rotated according to the female helicoid 24a and the male helicoid 29a via the interlocking protrusion 24c and moved to the in-focus position. The shutter block 24 has a shutter blade 24d that opens and closes according to a subject brightness signal from a photometric device (not shown).

On the inner peripheral surface of the third delivery lens barrel 22, three straight guide rails 22b extending forward are formed at equal intervals in a portion of the shutter block mounting member 23 that is away from the support arm portion 23a. Each straight guide rail 22b is engaged with a straight guide groove 21g formed on each straight key 21a of the straight moving member 21 and extending forward. With the above structure, when the second delivery barrel 20 is delivered, due to the engagement relationship between the linear guide rail 22b and the linear guide groove 21g, and the screwing relationship between the male helicoid 22a and the female helicoid 20a,
The third delivery lens barrel 22 rotates forward with respect to the second delivery lens barrel 20 and does not rotate relative to the fixed tubular member 13 and is extended forward.

A receiving space 23b is formed between the support arm portions 23a of the shutter block mounting member 23 along the inner peripheral surface of the third delivery barrel 22. That is, the shutter block mounting member 23 includes the support arm portion 23a and the receiving space 2
3b are alternately arranged in the circumferential direction. Each receiving space 23b
When the zoom lens barrel 10 is housed, the corresponding linear key 21a and drive arm portion 19c are housed therein. That is, when the zoom lens barrel 10 is stored, the support arm portion 23a, the straight advance key 21a, and the drive arm portion 19c are positioned on the same circumference as shown in FIG. Since the rotating member 19 rotates relative to the rectilinear movement member 21 and the shutter block mounting member 23, when the drive arm portion 19c enters the receiving space 23b, the drive arm portion 19c rotates to some extent and moves along with the rectilinear movement key 21a. The circumferential length L of the receiving space 23b is set to be a predetermined amount longer than the total length of the circumferential length of the drive arm portion 19c and the straight key 21a so that the receiving space 23b can enter. There is. A solid line 19c in FIG. 6 indicates the position of the drive arm portion 19c in the receiving space 23b when the zoom lens barrel is stored, and a dashed line 19c indicates that the drive arm portion 19c is the receiving space 23b.
The position of the drive arm portion 19c immediately after entering the inside is shown.

The present zoom lens barrel 10 having the above structure
Operates as follows. When the pinion shaft 15 is rotated by the zoom motor M, the first payoff lens barrel 18 is rotated by the pinion gear portion 15b and the outer peripheral gear portion 18b, and while being rotated, the first tubular lens barrel 18 is fixed by the relationship between the female helicoid 13a and the male helicoid 18a. It starts from 13. At the same time, the rotating member 19 rotates due to the relationship between the lead groove 13b and the engaging protrusion 19b. When the rotating member 19 rotates, the rotation of the rotating member 19 is transmitted to the second delivery barrel 20 via the drive arm portion 19c and the rotation transmission hole 20d, whereby the second delivery barrel 20 rotates and the female body rotates. Due to the relationship between the helicoid 18d and the male helicoid 20a, the helicoid 18d is extended from the first delivery barrel 18.

When the second delivery lens barrel 20 rotates, the rectilinear movement member 21 does not rotate relative to the fixed tubular member 13 due to the engagement relationship between the pin 21b and the lead groove 18e, and together with the second delivery lens barrel 20. Go straight ahead. By the rectilinear movement of the rectilinear movement member 21 and the rotation of the second payoff lens barrel 20, the rear lens group frame 28, that is, the rear lens group L2 is moved to the pin 2
It moves in the optical axis O direction depending on the relationship between 8a and the cam groove 20f. At the same time, when the second delivery lens barrel 20 rotates, the third delivery member 22, that is, the front lens group L1 is moved to the optical axis O by the relationship between the straight guide groove 21g and the straight guide rail 22b, and the relationship between the female helicoid 20e and the male helicoid 22a. Go straight in the direction. That is, the rotation of the second payoff lens barrel 20 causes the front lens group L1 and the rear lens group L2 to move along a predetermined locus in the optical axis O direction for zooming.

As described above, in the zoom lens barrel 10 to which the present invention is applied, the fixed tubular member 13 and the first to third delivery barrels 18, 20 and 22 are all coupled via the helicoid, and the As means for rotating the second feeding lens barrel 20, the rotation of the first feeding lens barrel 18 is transmitted to the second feeding lens barrel 20, and the first feeding lens barrel 18 is movable in the optical axis O direction and is the first feeding mirror. Since the rotation member 19 that can rotate relative to the barrel 18 is provided, the barrel-shaped member for driving the lens barrel and the drive provided inside the barrel are provided as compared with the conventional three-stage extension zoom lens barrel. It has succeeded in reducing the number of parts. As a result, in the present zoom lens barrel 10,
The expansion and contraction mechanism and the drive mechanism are simplified, and at the same time, the lens barrel is made compact in the radial direction. Further, when the zoom lens barrel 10 is stored, the support arm portion 23
Since the a, the straight advance key 21a and the drive arm portion 19c are arranged on the same circumference, the lens barrel can be made more compact in the radial direction.

[0024]

As described above, according to the three-stage extension zoom lens barrel of the present invention, the fixed tubular member and the first to third extension barrels are all helicoid-coupled, and the first extension barrel is formed. Driving means for rotating with respect to the fixed cylindrical member, and rotation of the second feeding lens barrel that is movable with the first feeding lens barrel in the optical axis direction and is rotatable relative to the first feeding lens barrel. Since the rotary member is provided, the expansion mechanism and the drive mechanism are simple, and the size of the lens barrel in the radial direction is not increased. Accordingly, for example, if the three-stage extension zoom lens barrel of the present invention is applied to a compact camera, it is possible to further reduce the height and width of the camera body.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a three-stage extension zoom lens barrel according to the present invention, in which the upper half section of the optical axis is in a stored state and the lower half section is in a maximum extended state. .

FIG. 2 is an exploded perspective view showing a main lens barrel driving member of the three-stage extension zoom lens barrel shown in FIG.

FIG. 3 is an enlarged perspective view of a second delivery barrel.

FIG. 4 is a view showing an inner peripheral surface of a fixed tubular member in a developed manner.

FIG. 5 is a diagram showing the outer peripheral surface of the first delivery lens barrel in a developed state, and further showing the relative positional relationship between the outer peripheral gear portion formed on the outer peripheral surface and the pinion shaft.

FIG. 6 is a cross-sectional view showing a positional relationship between a support arm of a shutter block mounting member, a rectilinear key of a rectilinear moving member, and a drive arm of a rotating member.

[Explanation of symbols]

10 Zoom lens barrel 13 Fixed tubular member 15 pinion shaft 18 First feeding lens barrel 19 Rotating member 20 Second feeding lens barrel 21 Straight-moving member 22 Third delivery barrel 23 Shutter block mounting member 24 shutter block L1 front lens L2 rear group lens

Continuation of the front page (56) References JP-A-7-27963 (JP, A) JP-A-8-5887 (JP, A) JP-A-7-13059 (JP, A) Actual Kaihei 6-54013 (JP , U) Actual Kaihei 2-117510 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 7/10 G02B 7/04 G02B 7/08

Claims (7)

(57) [Claims] 1. A fixed tubular member; a first delivery lens barrel helicoidally coupled to this fixed tubular member; a second delivery lens barrel helicoidally coupled to this first delivery lens barrel; and a second delivery thereof. A third delivery lens barrel helicoidally coupled to the lens barrel; a front lens group supported in the third delivery lens barrel; a rear lens group supported in the second delivery lens barrel; and the first delivery lens. Drive means for rotating the lens barrel with respect to the fixed tubular member; the second feeding lens barrel movable together with the first feeding lens barrel in the optical axis direction and rotatable relative to the first feeding lens barrel. And a rotating member for rotating the lens. 2. The three-stage extension zoom lens mirror according to claim 1, wherein the rotation member transmits the rotation of the first delivery barrel by the driving means to the second delivery barrel to rotate the second delivery barrel. Cylinder. 3. The three-stage extension zoom lens barrel according to claim 1, wherein a cam groove that defines a movement locus of the rear lens group is formed on the inner peripheral surface of the second extension lens barrel. 4. The third delivery lens barrel according to claim 1, wherein the third delivery lens barrel is movable in the optical axis direction together with the second delivery lens barrel, and is rotatable relative to the second delivery lens barrel. A 3-stage zoom lens barrel that is guided straight in the optical axis direction by a straight guide member. 5. The rotating member according to any one of claims 1 to 4, wherein the rotating member has a driving arm portion parallel to the optical axis,
A three-stage extension zoom lens barrel that transmits the rotation of the first extension barrel to the second extension barrel via the drive arm. 6. The linear movement guide member according to claim 5, wherein the linear movement guide member has a linear movement key portion parallel to the optical axis, and the linear movement key portion and the drive arm portion are arranged so as to move the optical axis when the zoom lens barrel is housed. A three-stage extension zoom lens barrel that is located in the receiving space formed along the inner peripheral surface of the third delivery barrel while being positioned on the same circumference as the center. 7. The lead groove according to claim 4, further formed on the inner peripheral surface of the first feeding lens barrel, the helicoid connecting the first feeding lens barrel and the second feeding lens barrel being tilted in an opposite direction. When;
When the second delivery lens barrel rotates, the linear guide member is provided with an engaging projection that engages with the lead groove and is provided by the engaging relationship between the lead groove and the engaging projection. A three-stage payout zoom lens barrel that moves integrally with the second payout barrel in the optical axis direction while rotating in a direction opposite to the rotation direction of the second payout barrel.